Aufnahme flüchtiger organischer Verbindungen durch Pflanzen

Miebach, M.

Diploma Thesis

Aufnahme flüchtiger organischer Verbindungen durch Pflanzen

Miebach, M. (Corresponding author)FZJ*

2003
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Jülich : Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag, Berichte des Forschungszentrums Jülich 4062, VII, 56 p. (2003) = Aachen, Fachhochsch., Abt. Jülich, Dipl. 2003

Please use a persistent id in citations: http://hdl.handle.net/2128/142

Report No.: Juel-4062

Abstract: Because volatile organic compounds (VOC) influence the radical balance and the photochemical ozone production in troposphere they play an important role for atmospheric chemistry. Thus, for atmospheric chemistry it is important to know the strength of VOC sources and VOC sinks. VOC emission from plants is well known. However, it is unclear whether or not plants can act as sinks for VOC. This was investigated in the present study. Sunflower (Helianthus annuus L.) was exposed to different VOC in laboratory experiments under well defined conditions. For individual VOC the concentrations were quantified using gas chromatography-mass spectrometry. A possible uptake by the plants was determined from the concentration differences between chamber inlet and outlet. In cases where a significant uptake by the plants was observed the flux densities were determined using the leaf area as a normalization factor. By variations of light intensity stomatal aperture was changed allowing to determine the passway of the individual VOC into the plant. For the compounds acetaldehyde, acetone, ethanol, isoprene, limonene und methanol no uptake by sunflower was observed. These substances were only emitted even if the plants were exposed to VOC concentrations above 50 ppb . For (E)-3-hexenol, hexanal, octanal and nopinone significant concentration differences between chamber inlet and outlet were found. It was ruled out that these loses were due to reactions in the gas phase or interferences at the walls of the analytic equipment. The data showed no significant deposition onto the plants cuticula but good relations between stomatal aperture and loss of the VOC. These relations showed a limitation of the uptake by diffusion through the Stomata for (E)-3-hexenol, hexanal, and octanal. For nopinone an internal resistance for the uptake was found. Furthermore, calculations showed Chat a solution of the compounds in the apoplasic water could not explain the uptake rates implying a metabolization of (E)-3-hexenol, hexanal, and octanal. Using the measured data it was shown Chat sunflowers are able to uptake up to 4 g hexanal per m$^{2}$ and day (12h) at an atmospheric mixing ration of 30 ppb. Dependent on the meteorological conditions and dependent on the individual VOC the loss by dry deposition onto plants can contribute to more Chan 20 % of the total loss from the atmosphere. In such cases dry deposition of VOC on plant surfaces cannot be neglected as a sink.

Note: Record converted from VDB: 12.11.2012
Note: Aachen, Fachhochsch., Abt. Jülich, Dipl. 2003

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